Category Archives: Google Summer of Code

DBpedia @ GSoC 2017 – Call for ideas & mentors

Dear DBpedians,

As previous years, we would like your input for DBpedia related project ideas for GSoC 2017.

For those who are unfamiliar with GSoC (Google Summer of Code), Google pays students (BSc, MSc, PhD) to work for 3 months on an open source project. Open source organizations announce their student projects and students apply for projects they like. After a selection phase, students are matched with a specific project and a set of mentors to work on the project during the summer.

Here you can see the Google Summer of Code 2017 timeline:

or please check:

If you have a cool idea for DBpedia or want to co-mentor an existing cool idea go here (All mentors get a free Google T-shirt and get the chance to go Google HQs in November.).

DBpedia applied for the fifth time to participate in the Google Summer of Code program. Here you will find a list of all projects and students from GSoC 2016:

Check our website for further updates, follow us on #twitter or subscribe to our newsletter.

Looking forward to your input.

Your DBpedia Association

Retrospective: 2nd US DBpedia Community meeting in California

After the largest DBpedia meeting to date we decided it was time to cross the Atlantic for the second time for another meetup. Two weeks ago the 8th DBpedia Community Meeting was held in Sunnyvale, California on October 27th 2016.

Main Event

Pablo Mendes from Lattice Data Inc. opened the main event with a short introduction setting the tone for the evening. After that Dimitris Kontokostas gave technical and organizational DBpedia updates. The main event attracted attendees with lightning talks from major companies actively using DBpedia or interested in knowledge graphs in general.

Four major institutions described their efforts to organize reusable information in a centralized knowledge representation. Google’s Tatiana Libman presented (on behalf of Denny Vrandečić) the impressive scale of the Google Knowledge graph, with 1B+ entities and over 100 billion facts.

Tatiana Libman from Google
Tatiana Libman from Google

Yahoo’s Nicolas Torzec presented the Yahoo knowledge graph, with focus on their research on extracting data from Web tables to expand their knowledge which includes DBpedia as an important part. Qi He from LinkedIn focused mostly on how to model a knowledge graph of people and skills, which becomes particularly interesting with the possibility of integration with Microsoft’s Satori Graph. Such an integration would allow general domain knowledge and very specific knowledge about professionals complementing one another. Stas Malyshev from Wikidata presented statistics on their growth, points of contact with DBpedia as well as an impressive SPARQL query interface that can be used to query the structured data that they are generating.

Three other speakers focused on the impact of DBpedia in machine learning and natural language processing. Daniel Gruhl from IBM Watson gave the talk “Truth for the impatient” where he showed that a knowledge model built from DBpedia can help costs and time to value for extracting entity mentions with higher accuracy. Pablo Mendes from Lattice Data Inc. presented their approach that leverages DBpedia and other structured information sources for weak supervision to obtain very strong NLP extractors. Sujan Perera from IBM Watson discussed the problem of identifying implicit mentions of entities in tweets and how the knowledge represented in DBpedia can be used to help uncover those references.

Another three speakers focused on applications of DBpedia and knowledge graphs. Margaret Warren from Metadata Authoring Systems, LLC presented ImageSnippets and how background knowledge from DBpedia allows better multimedia search through inference. For instance, by searching for “birds” you may find pictures that haven’t been explicitly tagged as birds but for which the fact can be inferred from DBpedia. Jans Aasman from Franz Inc presented their company’s approach to Data Exploration with Visual SPARQL Queries. They described opportunities for graph analytics in the medical domain, and discussed how DBpedia has been useful in their applications. Finally, Wang-Chiew Tan presented their research at RIT relating to building chatbots, among other projects that relate to using background knowledge stored in computers to enrich real life experiences.

Nicolas Torzec from Yahoo

Overall the talks were very high quality and fostered plenty of discussions afterwards. We finalized the event with a round of introductions where every attendee got to say their name and affiliation to help them connect with one another throughout the final hour of the event.

All slides and presentations are also available on our Website and you will find more feedback and photos about the event on Twitter via #DBpediaCA.

We would like to thank Yahoo for hosting the event, Google Summer of Code 2016 mentor summit as the reason we were in the area and collocated the DBpedia meeting, the Institute for Applied Informatics for supporting the DBpedia Association, ALIGNED – Software and Data Engineering for funding the development of DBpedia as a project use-case and last but not least OpenLink Software for continuous hosting the main DBpedia Endpoint.

Many thanks to Pablo Mendes for writing this blogpost :)

So now, we are looking forward to the next DBpedia community meeting which will be held in Europe again. We will keep you informed via the DBpedia Website and Blog.

Your DBpedia Association

DBpedia @ Google Summer of Code 2016

DBpedia participated for a fourth time in the Google summer of code program. This was a quite competitive year (like every year) where more than fourty students applied for a DBpedia project. In the end,  8 great students from all around the world  were selected and will work on their projects during the summer. Here’s a detailed list of the projects:

A Hybrid Classifier/Rule-based Event Extractor for DBpedia Proposal by Vincent Bohlen

In modern times the amount of information published on the internet is growing to an immeasurable extent. Humans are no longer able to gather all the available information by hand but are more and more dependent on machines collecting relevant information automatically. This is why automatic information extraction and in especially automatic event extraction is important. In this project I will implement a system for event extraction using Classification and Rule-based Event Extraction. The underlying data for both approaches will be identical. I will gather wikipedia articles and perform a variety of NLP tasks on the extracted texts. First I will annotate the named entities in the text using named entity recognition performed by DBpedia Spotlight. Additionally I will annotate the text with Frame Semantics using FrameNet frames. I will then use the collected information, i.e. frames, entities, entity types, with the aforementioned two different methods to decide if the collection is an event or not. Mentor: Marco Fossati (SpazioDati)

Automatic mappings extraction by Aditya Nambiar

DBpedia currently maintains a mapping between Wikipedia info-box properties to the DBpedia ontology, since several similar templates exist to describe the same type of info-boxes. The aim of the project is to enrich the existing mapping and possibly correct the incorrect mapping’s using Wikidata.

Several wikipedia pages use Wikidata values directly in their infoboxes. Hence by using the mapping between Wikidata properties and DBpedia Ontology classes along with the info-box data across several such wiki pages we can collect several such mappings. The first phase of the project revolves around using various such wikipedia templates , finding their usages across the wikipedia pages and extracting as many mappings as possible.

In the second half of the project we use machine learning techniques to take care of any accidental / outlier usage of Wikidata mappings in wikipedia. At the end of the project we will be able to obtain a correct set of mapping which we can use to enrich the existing mapping. Mentor: Markus Freudenberg (AKSW/KILT)

Combining DBpedia and Topic Modelling by wojtuch

DBpedia, a crowd- and open-sourced community project extracting the content from Wikipedia, stores this information in a huge RDF graph. DBpedia Spotlight is a tool which delivers the DBpedia resources that are being mentioned in the document.

Using DBpedia Spotlight to extract Named Entities from Wikipedia articles and then applying a topic modelling algorithm (e.g. LDA) with URIs of DBpedia resources as features would result in a model, which is capable of describing the documents with the proportions of the topics covering them. But because the topics are also represented by DBpedia URIs, this approach could result in a novel RDF hierarchy and ontology with insights for further analysis of the emerged subgraphs.

The direct implication and first application scenario for this project would be utilizing the inference engine in DBpedia Spotlight, as an additional step after the document has been annotated and predicting its topic coverage. Mentor: Alexandru Todor (FU Berlin)

DBpedia Lookup Improvements by Kunal.Jha

DBpedia is one of the most extensive and most widely used knowledge base in over 125 languages. DBpedia Lookup is a tool that allows The DBpedia Lookup is a web service that allows users to obtain various DBpedia URIs for a given label (keywords/anchor texts). The service provides two different types of search APIs, namely, Keyword Search and Prefix Search. The lookup service currently returns the query results in XML (default) and JSON formats and works on English language. It is based on a Lucene Index providing a weighted label lookup, which combines string similarity with a relevance ranking in order to find the most relevant matches for a given label. As a part of the GSOC 2016, I propose to implement improvisations with an intention to make the system more efficient and versatile. Mentor: Axel Ngonga (AKSW)

Inferring infobox template class mappings from Wikipedia + Wikidata by Peng_Xu

This project aims at finding mappings between the classes (eg. dbo:Person, dbo:City) in the DBpedia ontology and infobox templates on pages of Wikipedia resources using machine learning. Mentor: Nilesh Chakraborty (University of Bonn)

Integrating RML in the Dbpedia extraction framework by wmaroy

This project is about integrating RML in the Dbpedia extraction framework. Dbpedia is derived from Wikipedia infoboxes using the extraction framework and mappings defined using the wikitext syntax. A next step would be replacing the wikitext defined mappings with RML. To accomplish this, adjustments will have to be made to the extraction framework. Mentor: Dimitris Kontokostas (AKSW/KILT)

The List Extractor by FedBai

The project focuses on the extraction of relevant but hidden data which lies inside lists in Wikipedia pages. The information is unstructured and thus cannot be easily used to form semantic statements and be integrated in the DBpedia ontology. Hence, the main task consists in creating a tool which can take one or more Wikipedia pages with lists within as an input and then construct appropriate mappings to be inserted in a DBpedia dataset. The extractor must prove to work well on a given domain and to have the ability to be expanded to reach generalization. Mentor: Marco Fossati (SpazioDati)

The Table Extractor by s.papalini

Wikipedia is full of data hidden in tables. The aim of this project is to exploring the possibilities of take advantage of all the data represented with the appearance of tables in Wiki pages, in order to populate the different versions of DBpedia with new data of interest. The Table Extractor has to be the engine of this data “revolution”: it would achieve the final purpose of extract the semi structured data from all those tables now scattered in most of the Wiki pages. Mentor: Marco Fossati (SpazioDati)

At the begining of September 2016 you will receive news about successfull Google Summer of Code 2016 student projects. Stay tuned and follow us on  facebook, twitter or visit our website for the latest news.

Your DBpedia Association

We proudly present our new 2015-10 DBpedia release, which is abailable now via: Go an check it out!

This DBpedia release is based on updated Wikipedia dumps dating from October 2015 featuring a significantly expanded base of information as well as richer and cleaner data based on the DBpedia ontology.

So, what did we do?

The DBpedia community added new classes and properties to the DBpedia ontology via the mappings wiki. The DBpedia 2015-10 ontology encompasses

  • 739 classes (DBpedia 2015-04: 735)
  • 1,099 properties with reference values (a/k/a object properties) (DBpedia 2015-04: 1,098)
  • 1,596 properties with typed literal values (a/k/a datatype properties) (DBpedia 2015-04: 1,583)
  • 132 specialized datatype properties (DBpedia 2015-04: 132)
  • 407 owl:equivalentClass and 222 owl:equivalentProperty mappings external vocabularies (DBpedia 2015-04: 408 and 200, respectively)

The editors community of the mappings wiki also defined many new mappings from Wikipedia templates to DBpedia classes. For the DBpedia 2015-10 extraction, we used a total of 5553 template mappings (DBpedia 2015-04: 4317 mappings). For the first time the top language, gauged by number of mappings, is Dutch (606 mappings), surpassing the English community (600 mappings).

And what are the (breaking) changes ?

  • English DBpedia switched to IRIs from URIs. 
  • The instance-types dataset is now split to two files:
    • “instance-types” contains only direct types.
    • “Instance-types-transitive” contains transitive types.
    • The “mappingbased-properties” file is now split into three (3) files:
      • “geo-coordinates-mappingbased”
      • “mappingbased-literals” contains mapping based statements with literal values.
      • “mappingbased-objects”
  • We added a new extractor for citation data.
  • All datasets are available in .ttl and .tql serialization 
  • We are providing DBpedia as a Docker image.
  • From now on, we provide extensive dataset metadata by adding DataIDs for all extracted languages to the respective language directories.
  • In addition, we revamped the dataset table on the download-page. It’s created dynamically based on the DataID of all languages. Likewise, the tables on the statistics- page are now based on files providing information about all mapping languages.
  • From now on, we also include the original Wikipedia dump files(‘pages_articles.xml.bz2’) alongside the extracted datasets.
  • A complete changelog can always be found in the git log.

And what about the numbers?

Altogether the new DBpedia 2015-10 release consists of 8.8 billion (2015-04: 6.9 billion) pieces of information (RDF triples) out of which 1.1 billion (2015-04: 737 million) were extracted from the English edition of Wikipedia, 4.4 billion (2015-04: 3.8 billion) were extracted from other language editions, and 3.2 billion (2015-04: 2.4 billion) came from  DBpedia Commons and Wikidata. In general we observed a significant growth in raw infobox and mapping-based statements of close to 10%.  Thorough statistics are available via the Statistics page.

And what’s up next?

We will be working to move away from the mappings wiki but we will have at least one more mapping sprint. Moreover, we have some cool ideas for GSOC this year. Additional mentors are more than welcome. :-)

And who is to blame for the new release?

We want to thank all editors that contributed to the DBpedia ontology mappings via the Mappings Wiki, all the GSoC students and mentors working directly or indirectly on the DBpedia release and the whole DBpedia Internationalization Committee for pushing the DBpedia internationalization forward.

Special thanks go to Markus Freudenberg and Dimitris Kontokostas (University of Leipzig), Volha Bryl (University of Mannheim / Springer), Heiko Paulheim (University of Mannheim), Václav Zeman and the whole LHD team (University of Prague), Marco Fossati (FBK), Alan Meehan (TCD), Aldo Gangemi (LIPN University, France & ISTC-CNR, Italy), Kingsley Idehen, Patrick van Kleef, and Mitko Iliev (all OpenLink Software), OpenLink Software (, Ruben Verborgh from Ghent University – iMinds, Ali Ismayilov (University of Bonn), Vladimir Alexiev (Ontotext) and members of the DBpedia Association, the AKSW and the department for Business Information Systems of the University of Leipzig for their committment in putting tremendous time and effort to get this done.

The work on the DBpedia 2015-10 release was financially supported by the European Commission through the project ALIGNED – quality-centric, software and data engineering  (


Detailed information about the new release are available here. For more information about DBpedia, please visit our website or follow us on Facebook!

Have fun and all the best!


DBpedia Association

GSoC 2015 is gone, long live GSoC 2016

The submission deadline for mentoring organizations to submit their application for the 2016 Google Summer of Code is approaching quickly. As DBpedia is again planning to be a vital part of the Mentoring Summit, we like to take that opportunity to  give you a little recap of the projects mentored by DBpedia members during the past GSoC, in November 2015. 

Dimitris Kontokostas, Marco Fossati, Thiago Galery, Joachim Daiber and Reuben Verborgh, members of the Dbpedia community, mentored 8 great students from around the world. Following are some of the projects they completed.

Fact Extraction from Wikipedia Text by Emilio Dorigatti

DBpedia is pretty much mature when dealing with Wikipedia semi-structured content like infoboxes, links and categories. However, unstructured content (typically text) plays the most crucial role, due to the amount of knowledge it can deliver, and few efforts have been carried out to extract structured data out of it. Marco and Emilio built a fact extractor, which understands the semantics of a sentence thanks to Natural Language Processing (NLP) techniques. If you feel playful, you can download the produced datasetsFor more details, check out this blog postP.S.: the project has been cited by Python Weekly and Python TrendingMentor: Marco Fossati (SpazioDati)

Better context vectors for disambiguation by Philipp Dowling

Better Context Vectors  aimed to improve the representation of context used by DBpedia Spotlight by incorporating novel methods from distributional semantics. We investigated the benefits of replacing a word-count based method for one that uses a model based on word2vec. Our student, Philipp Dowling, implemented the model reader based on a preprocessed version of Wikipedia (leading to a few commits to the awesome library gensim) and the integration with the main DBpedia Spotlight pipeline. Additionally, we integrated a method for estimating weights for the different model components that contribute to disambiguating entities. Mentors: Thiago Galery (Analytyca), Joachim Daiber (Amsterdam Univ.), David Przybilla (Idio)


Wikipedia Stats Extractor by Naveen Madhire

Wikipedia Stats Extractor aimed to create a reusable tool to extract raw statistics for Name Entity Linking out of a Wikipedia dump. Naveen built the project on top of Apache Spark and Json-wikipedia which makes the code more maintainable and faster than its previous alternative (pignlproc). Furthermore Wikipedia Stats Extractor provides an interface which makes easier the task of processing Wikipedia dumps for  purposes other than Entity Linking. Extra changes were made in the way surface forms stats are extracted  and lots of noise was removed, both of which should in principle help Entity Linking.
Special regards to Diego Ceccarelli who gave us great insight on how Json-wikipedia worked. Mentors: Thiago Galery (Analytyca), Joachim Daiber (Amsterdam Univ.), David Przybilla (Idio)


DBpedia Live extensions by Andre Pereira

DBpedia Live provides near real-time knowledge extraction from Wikipedia. As wikipedia scales we needed to move our caching infrastructure from MySQL to MongoDB. This was the first task of Andre’s project. The second task was the implementation of a UI displaying the current status of DBpedia Live along with some admin utils. Mentors: Dimitris Kontokostas (AKSW/KILT), Magnus Knuth (HPI)


Adding live-ness to the Triple Pattern Fragments server by Pablo Estrada

DBpedia currently has a highly available Triple Pattern Fragments interface that offloads part of the query processing from the server into the clients. For this GSoC, Pablo developed a new feature for this server so it automatically keeps itself up to date with new data coming from DBpedia Live. We do this by periodically checking for updates, and adding them to an auxiliary database. Pablo developed smart update, and smart querying algorithms to manage and serve the live data efficiently. We are excited to let the project out in the wild, and see how it performs in real-life use cases. Mentors: Ruben Verborgh (Ghent Univ. – iMinds) and Dimitris Kontokostas (AKSW/KILT)

Registration for mentors @ GSoC 2016 is starting next month and DBpedia would of course try to participate again. If you want to become a mentor or just have a cool idea that seems suitable, don’t hesitate to ping us via the DBpedia discussion or developer mailing lists.

Stay tuned!

Your DBpedia Association

DBpedia Spotlight V0.7 released

DBpedia Spotlight is an entity linking tool for connecting free text to DBpedia through the recognition and disambiguation of entities and concepts from the DBpedia KB.

We are happy to announce Version 0.7 of DBpedia Spotlight, which is also the first official release of the probabilistic/statistical implementation.

More information about as well as updated evaluation results for DBpedia Spotlight V0.7 are found in this paper:

Joachim Daiber, Max Jakob, Chris Hokamp, Pablo N. Mendes: Improving Efficiency and Accuracy in Multilingual Entity ExtractionISEM2013. 

The changes to the statistical implementation include:

  • smaller and faster models through quantization of counts, optimization of search and some pruning
  • better handling of case
  • various fixes in Spotlight and PigNLProc
  • models can now be created without requiring a Hadoop and Pig installation
  • UIMA support by @mvnural
  • support for confidence value

See the release notes at [1] and the updated demos at [4].

Models for Spotlight 0.7 can be found here [2].

Additionally, we now provide the raw Wikipedia counts, which we hope will prove useful for research and development of new models [3].

A big thank you to all developers who made contributions to this version (with special thanks to Faveeo and Idio). Huge thanks to Jo for his leadership and continued support to the community.

Pablo Mendes,

on behalf of Joachim Daiber and the DBpedia Spotlight developer community.

[1] –

[2] –

[3] –

[4] –

(This message is an adaptation of Joachim Daiber’s message to the DBpedia Spotlight list. Edited to suit this broader community and give credit to him.)

Call for Ideas and Mentors for GSoC 2014 DBpedia + Spotlight joint proposal (please contribute within the next days)

We started to draft a document for submission at Google Summer of Code 2014:

We are still in need of ideas and mentors.  If you have any improvements on DBpedia or DBpedia Spotlight that you would like to have done, please submit it in the ideas section now. Note that accepted GSoC students will receive about 5000 USD for a three months, which can help you to estimate the effort and size of proposed ideas. It is also ok to extend/amend existing ideas (as long as you don’t hi-jack them). Please edit here:

Becoming a mentor is also a very good way to get involved with DBpedia. As a mentor you will also be able to vote on proposals, after Google accepts our project. Note that it is also ok, if you are a researcher and have a suitable student to submit an idea and become mentor. After acceptance by Google the student then has to apply for the idea and get accepted.

Please take some time this week to add your ideas and apply as a mentor, if applicable. Feel free to improve the introduction as well and comment on the rest of the document.

Information on GSoC in general can be found here:

Thank you for your help,
Sebastian and Dimitris

Making sense out of the Wikipedia categories (GSoC2013)

(Part of our DBpedia+spotlight @ GSoC mini blog series)

Mentor: Marco Fossati @hjfocs <fossati[at]>
Student: Kasun Perera <kkasunperera[at]>

The latest version of the DBpedia ontology has 529 classes. It is not well balanced and shows a lack of coverage in terms of encyclopedic knowledge representation.

Furthermore, the current typing approach involves a costly manual mapping effort and heavily depends on the presence of infoboxes in Wikipedia articles.

Hence, a large number of DBpedia instances is either un-typed, due to a missing mapping or a missing infobox, or has a too generic or too specialized type, due to the nature of the ontology.

The goal of this project is to identify a set of senseful Wikipedia categories that can be used to extend the coverage of DBpedia instances.

How we used the Wikipedia category system

Wikipedia categories are organized in some kind of really messy hierarchy, which is of little use from an ontological point of view.

We investigated how to process this chaotic world.

Here’s what we have done

We have identified a set of meaningful categories by combining the following approaches:

  1. Algorithmic, programmatically traversing the whole Wikipedia category system.

Wow! This was really the hardest part. Kasun made a great job! Special thanks to the category guru Christian Consonni for shedding light in the darkness of such a weird world.

  1. Linguistic, identifying conceptual categories with NLP techniques.

We got inspired by the YAGO guys.

  1. Multilingual, leveraging interlanguage links.

Kudos to Aleksander Pohl for the idea.

  1. Post-mortem, cleaning out stuff that was still not relevant

No resurrection without Freebase!


We found out a total amount of 3751 candidates that can be used to type the instances.

We produced a dataset in the following format:

<Wikipedia_article_page> rdf:type <article_category>

You can access the full dump here. This has not been validated by humans yet.

If you feel like having a look at it, please tell us what do you think about.

Take a look at the Kasun’s progress page for more details.